A grid of eighteen cartoon smiley faces scrolls vertically, each rendered with randomized facial features. The example demonstrates reusable React components—`FaceContainer`, `BackgroundCircle`, `Eyes`, and `Mouth`—composed to build the SVG output. The `Mouth` component uses D3’s `arc` generator to create a smile path, while `index.js` generates the array of faces using `d3.range`, applying random values for stroke width, eye offsets, and mouth dimensions.